Crossbow

ABSTRACT

A crossbow has a body, a bow, two pulley assemblies, and a string. The bow is resilient, is mounted on a front end of the body, and has two limbs extending respectively toward two sides of the body. The pulley assemblies are mounted respectively on free ends of the two limbs. Each roller assembly has a string pulley, an idle wheel, and a cable. The cable has a front end connected securely with the front end of the body and a rear end mounted around the idle wheel of the pulley assembly and the string pulley of the other pulley assembly and securely connected with the string pulley of the other pulley assembly. The string is mounted around the string pulleys of the pulley assemblies and has two ends connected securely with the string pulleys of the pulley assemblies.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a crossbow, and more particularly to a crossbow that has idle wheels to prolong the useful life of the crossbow.

2. Description of Related Art

With reference to FIG. 6, a conventional crossbow comprises a body 60, a first limb 70A, a second limb 70B, a first pulley assembly 80A, a second pulley assembly 80B, and a string 90. The first limb 70A and the second limb 70B are connected with the body 60. The first pulley assembly 80A is mounted on the first limb 70A and comprises a first pulley 81A and a first cable 82A. The first pulley 81A is mounted rotatably on a free end of the first limb 70A. The first cable 82A is mounted around the first pulley 81A and is connected securely with the second limb 70B. The second pulley assembly 80B is mounted on the second limb 70B and comprises a second pulley 81B and a second cable 82B. The second pulley 81B is mounted rotatably on a free end of the second limb 70B. The second cable 82A is mounted around the second pulley 81B and is connected securely with the first limb 70A. The string 90 is mounted around the first pulley 81A and the second pulley 81B and has two ends connected respectively with the first pulley 81A and the second pulley 81B.

With reference further to FIG. 7, when the string 90 is pulled, the first pulley 81A and the second pulley 81B are driven to rotate by the string 90. The first cable 82A and the second cable 82B are partially rolled around the first pulley 81A and the second pulley 81B, and the free ends of the first and second limbs 70A, 70B are bent toward the body 60. Because the first cable 82A and the second cable 82B are connected securely with the first limb 70A and the second limb 70B respectively, the rolled length of the cables 82, 82B onto the pulleys 781A, 81B will determine the bent degrees of the limbs 70A, 70B. The limbs 70A, 70B may be overly bent in each operation of the crossbow, such that the limbs 70A, 70B easily elastically fatigue. Therefore, the useful life of the crossbow will be shortened.

To overcome the shortcomings, the present invention tends to provide a crossbow to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the invention is to provide a crossbow to prolong the useful life of the crossbow.

The crossbow has a body, a bow, two pulley assemblies, and a string. The body has a front end and a rear end. The bow is resilient, is mounted on the front end of the body, and has two limbs. The two limbs extend respectively toward two sides of the body. Each limb has a free end away from the body. The pulley assemblies are mounted respectively on the free ends of the two limbs. Each roller assembly has a string pulley, an idle wheel, and a cable. The string pulley is mounted rotatably on the free end of a corresponding one of the limbs. The idle wheel is mounted rotatably on the free end of the corresponding one of the limbs. The cable has a front end connected securely with the front end of the body and a rear end mounted around the idle wheel of the pulley assembly and the string pulley of the other one of the pulley assemblies and securely connected with the string pulley of the other one of the pulley assemblies. The string is mounted around the string pulleys of the pulley assemblies and has two ends connected securely with the string pulleys of the pulley assemblies.

Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a crossbow in accordance with the present invention;

FIG. 2 is an enlarged exploded perspective view of the pulley assembly of the crossbow in FIG. 1;

FIG. 3 is a bottom view of the crossbow in FIG. 1;

FIG. 4 is an enlarged bottom view of the cable mount of the crossbow in FIG. 3;

FIG. 5 is an operational bottom view of the crossbow in FIG. 1;

FIG. 6 is a perspective view of a conventional crossbow;

FIG. 7 is a bottom view of the conventional crossbow in FIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

With reference to FIG. 1, a crossbow in accordance with the present invention comprises a body 10, a bow 20, two pulley assemblies 30, and a string 40. The bow 20 is mounted on the body 10. The pulley assemblies 30 are mounted on the bow 20. The string 40 is mounted on the pulley assemblies 30.

The body 10 comprises a holding segment 11, an arrow mount 12, a bow mount 13, and a trigger assembly 14. The holding segment 11 comprises a buttstock 111 and a front grip 112. The buttstock 111 is formed on a rear end of the body 10. The front grip 112 is integrally connected with the buttstock 111 and extends along a longitudinal direction of the body 10 and toward a front end of the body 10. The arrow mount 12 is mounted on the holding segment 11, extends along the longitudinal direction of the body 10 and toward the front end of the body 10, and has an arrow recess defined in the arrow mount 12. The arrow recess extends along the longitudinal direction of the body 10 and toward the front end of the body 10 and is applied to hold an arrow inside. The bow mount 13 is mounted on the front end of the body 10 and is connected with the arrow mount 12. The trigger assembly 14 is connected with the arrow mount 12 and has a trigger 141 mounted on the holding segment 11.

The bow 20 is resilient and is mounted on the front end of the body 10. The bow 20 is connected with the bow mount 13 and comprises two limbs 21. The limbs 21 extend respectively toward two sides of the body 10, and each limb 21 has a free end away from the body 10. In this embodiment, the two limbs 21 are individual components and are connected securely with the bow mount 13 with fasteners, such as screws. Alternatively, the bow 20 is an integral component. Preferably, each limb 21 comprises two resilient arm elements 211, and a fastener, such as a screw, is mounted through the arm elements 211 and is connected to the bow mount 13 to securely mount the limb 21 on the bow mount 13. Alternatively, each limb 21 is an integral component. The structures and configurations of the bow 20 and the limbs 21 are not limited in the present invention.

With reference to FIGS. 1 and 2, the pulley assemblies 30 are respectively mounted rotatably on the free ends of the limbs 21. Each pulley assembly 30 comprises a string pulley 31, an idle wheel 32, a cable mount 33, and a cable 34. The string pulley 31 is mounted rotatably on a corresponding one of the limbs 21 along an axis X. The idle wheel 32 is mounted rotatably on the corresponding limb 21 along the axis X and has a cable groove 321. Preferably, each pulley assembly 30 further has an axle 35, and the string pulley 31 and the idle wheel 32 are co-axially mounted around the axle 35. Accordingly, the string pulley 31 and the idle wheel 32 are co-axially mounted on the corresponding limb 21. The string pulley 31 may be an eccentric cam. With further reference to FIGS. 3 and 4, the cable mount 33 is mounted on a side of the bow mount 13 facing the rear end of the body 10. The cable mount 33 has a cable groove 331 formed around the cable mount 33. The cable 34 has a front end and a rear end. The front end of the cable 34 is mounted in and around the cable groove 331 in the cable mount 33. The rear end of the cable 34 is mounted around the cable groove 321 in the idle wheel 32 and the string pulley 31 of the other pulley assembly 30 and is connected securely with the string pulley 31 of the other pulley assembly 30.

The string 40 is mounted around the string pulleys 31 of the pulley assemblies 30 and has two ends connected securely with the string pulleys 31 of the pulley assemblies 30.

With reference to FIG. 3, the two limbs 21 include a first limb 21A and a second limb 21B. The pulley assemblies 30 include a first pulley assembly 30A mounted on the first limb 21A and a second pulley assembly 30B mounted on the second limb 21B. The first pulley assembly 30A comprises a first string pulley 31A, a first idle wheel 32A, and a first cable 34A. The second pulley assembly 30B comprises a second string pulley 31B, a second idle wheel 32B, and a second cable 34B. The first cable 34A extends from the front end of the body 10 toward the free end of the first limb 21A, is mounted around the first idle wheel 32A, extends toward the free end of the second limb 21B, is mounted around the second string pulley 31B, and is securely connected with the second string pulley 31B. The second cable 34B extends from the front end of the body 10 toward the free end of the second limb 21B, is mounted around the second idle wheel 32B, extends toward the free end of the first limb 21A, is mounted around the first string pulley 31A, and is securely connected with the first string pulley 31A.

With reference to FIGS. 3 to 5, when the string 40 is pulled toward the rear end of the body 10, the string pulleys 31A, 31B will be rotated by the string 40. The cable 34A, 34B will be partially rolled around the string pulleys 31A, 31B by the rotation of the string pulleys 31A, 31B. Because the cables 34A, 34B extend respectively around the idle wheels 32A, 32B and the limbs 21A, 21B are resilient, the idle wheels 32A, 32B will be pulled toward the body 10 by the cables 34A, 34B and the free ends of the limbs 21A, 21B are also pulled toward the body 10. Consequently, the limbs 21A, 21B are bent. With the arrangement of the idle wheels 32A, 32B, the idle wheels 32A, 32B can serve as moving pulleys, such that the distances D of the idle wheels 32A, 32B moved toward the body 10 can be reduced. Accordingly, the bent degrees of the limbs 21A, 21B can be reduced.

Because the bent degrees of the limbs 21A, 21B are reduced, the stresses applied to the limbs 21A, 21B and the strains of the limbs 21A, 21B can be effectively reduced. Thus, elastic fatigue of the limbs 21A, 21B can be mitigated to prolong the useful life of the limbs 21A, 21B. With the reduced bent deformation of the limbs 21A, 21B, vibrations caused by the rebound of the limbs 21A, 21B can also be reduced. In addition, because the stresses applied onto the limbs 21A, 21B are reduced, the stress applied to the bow mount 13 connected with the limbs 21A, 21B can also be reduced. Thus, the bow mount can be made of a light material, such that the total light of and the cost for manufacturing the crossbow in accordance with the present invention can be effectively decreased.

Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

What is claimed is:
 1. A crossbow comprising: a body having a front end and a rear end; a bow being resilient, mounted on the front end of the body, and comprising two limbs extending respectively toward two sides of the body, and each limb having a free end away from the body; two pulley assemblies mounted respectively on the free ends of the two limbs, and each pulley assembly comprising a string pulley mounted rotatably on the free end of a corresponding one of the limbs; an idle wheel mounted rotatably on the free end of the corresponding one of the limbs; a cable having a front end connected securely with the front end of the body and a rear end mounted around the idle wheel of the pulley assembly and the string pulley of the other one of the pulley assemblies and securely connected with the string pulley of the other one of the pulley assemblies; and a string mounted around the string pulleys of the pulley assemblies and having two ends connected securely with the string pulleys of the pulley assemblies.
 2. The crossbow as claimed in claim 1, wherein the body has a bow mount mounted on the front end of the body; and each pulley assembly further comprises a cable mount mounted on a side of the bow mount facing the rear end of the body, wherein the front end of the cable of the pulley assembly is connected securely with the cable mount.
 3. The crossbow as claimed in claim 2, wherein the cable mount of each pulley assembly has an annular groove formed around the cable mount; and the front end of the cable of each pulley assembly is mounted in and around the annular groove in the cable mount of the pulley assembly.
 4. The crossbow as claimed in claim 3, wherein the string pulley and the idle wheel of each pulley assembly are co-axially connected with each other.
 5. The crossbow as claimed in claim 4, wherein each pulley assembly further has an axle around which the string pulley and the idle wheel of the pulley assembly is mounted.
 6. The crossbow as claimed in claim 5, wherein each limb comprises two resilient arm elements connected securely with the bow mount with a fastener.
 7. The crossbow as claimed in claim 6, wherein the idle wheel of each pulley assembly has a cable groove formed around the idle wheel; and the cable of each pulley assembly is mounted in the cable groove in the idle wheel of the pulley assembly.
 8. The crossbow as claimed in claim 5, wherein the idle wheel of each pulley assembly has a cable groove formed around the idle wheel; and the cable of each pulley assembly is mounted in the cable groove in the idle wheel of the pulley assembly.
 9. The crossbow as claimed in claim 4, wherein the idle wheel of each pulley assembly has a cable groove formed around the idle wheel; and the cable of each pulley assembly is mounted in the cable groove in the idle wheel of the pulley assembly.
 10. The crossbow as claimed in claim 3, wherein the idle wheel of each pulley assembly has a cable groove formed around the idle wheel; and the cable of each pulley assembly is mounted in the cable groove in the idle wheel of the pulley assembly.
 11. The crossbow as claimed in claim 2, wherein the idle wheel of each pulley assembly has a cable groove formed around the idle wheel; and the cable of each pulley assembly is mounted in the cable groove in the idle wheel of the pulley assembly.
 12. The crossbow as claimed in claim 1, wherein the idle wheel of each pulley assembly has a cable groove formed around the idle wheel; and the cable of each pulley assembly is mounted in the cable groove in the idle wheel of the pulley assembly.
 13. The crossbow as claimed in claim 1, wherein the string pulley and the idle wheel of each pulley assembly are co-axially connected with each other.
 14. The crossbow as claimed in claim 1, wherein each pulley assembly further has an axle around which the string pulley and the idle wheel of the pulley assembly is mounted.
 15. The crossbow as claimed in claim 1, wherein each limb comprises two resilient arm elements connected securely with the bow mount with a fastener. 